The use of balloon catheters for a variety of treatment procedures has risen greatly in recent years. Advancements in catheter procedures have led to more and more uses in different areas of the body for balloon catheters. Balloon catheters often require some sort of inflation device to create pressure for inflating a balloon once the catheter has been introduced into a patient's body and advanced to a proper location for inflation.
The inflation device coupled to a balloon catheter often functions as a modified syringe. A syringe is a device including a cylindrical chamber having openings on both ends; one opening is usually a small opening and the other is comparatively large. A plunger which slidably, yet sealingly fits the inner walls of the cylindrical chamber may be advanced from the larger opening toward the smaller opening to force a fluid through the smaller opening, and, oppositely, the plunger may be pulled from the smaller opening toward the larger opening to suck a fluid into the cylindrical chamber through the smaller opening. The plunger is usually attached to one end of a shaft with the other end of the shaft protruding out the larger opening of the syringe. Inflation devices for use with balloon catheters often modify the basic syringe just described by using a threaded shaft coupled to a threaded knob to advance and withdraw the plunger.
Occasionally during a procedure, a patient may begin to feel discomfort or pain due to the inflation of a catheter balloon. In some instances, the discomfort or pain may be an indicator of potentially serious problems with the procedure. For example, during a percutaneous transluminal coronary angioplasty, a patient's discomfort or pain may indicate initiation of tissue death due to lack of oxygen. In such a situation, it becomes desirable to quickly deflate the balloon to restore more normal body functions including, in some cases, normal blood flow and oxygenation. In other procedures, damage or tearing of tissue expanded by inflation of the balloon, the cutting off of fluid flow, or patient discomfort and pain may arise as a result of balloon inflation. In such situations, it would be desirable to have reliable devices for quickly reducing the pressure inside a catheter balloon.
One of the problems facing physicians is that, because many components used in catheter devices are relatively flexible metals or plastics, the threads holding the plunger in place in the inflation device at a high pressure may temporarily deform under strain, or may simply become more “sticky” due to friction between components at higher pressures, making it difficult to release pressure built up inside the balloon. Therefore, it is a goal of the present invention to provide a way to more quickly release pressure in a catheter balloon.